Roberto Moretti, Danilo Labranca, Pietro Campana
et al.
This study presents the design, simulation, and experimental characterization of a superconducting transmon qubit circuit prototype for potential applications in dark matter detection experiments. We describe a planar circuit design featuring two noninteracting transmon qubits, one with fixed frequency and the other flux tunable. Finite-element simulations were employed to extract key Hamiltonian parameters and optimize component geometries. The qubit was fabricated and then characterized at 20 mK, allowing for a comparison between simulated and measured qubit parameters. Good agreement was found for transition frequencies and anharmonicities (within 1% and 10%, respectively) while coupling strengths exhibited larger discrepancies (30%). We discuss potential causes for measured coherence times falling below expectations (<inline-formula><tex-math notation="LaTeX">$T_{1}\sim \,$</tex-math></inline-formula>1–2 <italic>μ</italic>s) and propose strategies for future design improvements. Notably, we demonstrate the application of a hybrid 3D–2D simulation approach for energy participation ratio evaluation, yielding a more accurate estimation of dielectric losses. This work represents an important first step in developing planar quantum nondemolition single-photon counters for dark matter searches, particularly for axion and dark photon detection schemes.
Atomic physics. Constitution and properties of matter, Materials of engineering and construction. Mechanics of materials
Quantum computers are a revolutionary class of computational platforms with applications in combinatorial and global optimization, machine learning, and other domains involving computationally hard problems. While these machines typically operate on qubits—quantum information elements that can occupy superpositions of the basis <inline-formula><tex-math notation="LaTeX">$|0\rangle$</tex-math></inline-formula> and <inline-formula><tex-math notation="LaTeX">$|1\rangle$</tex-math></inline-formula> states—recent advances have demonstrated the practical implementation of higher dimensional quantum systems (qudits) across various hardware platforms. In these hardware realizations, the higher order states are less stable, and thus remain coherent for a shorter duration than the basis <inline-formula><tex-math notation="LaTeX">$|0\rangle$</tex-math></inline-formula> and <inline-formula><tex-math notation="LaTeX">$|1\rangle$</tex-math></inline-formula> states. Moreover, formal methods for designing efficient encoder circuits for these systems remain underexplored. This limitation motivates the development of efficient circuit techniques for qudit systems (<italic>d</italic>-level quantum systems). Previous works have typically established generating gate sets for higher dimensional codes by generalizing the methods used for qubits. In this work, we introduce a systematic framework for optimizing encoder circuits for prime-dimension stabilizer codes. This framework is based on novel generating gate sets whose elements map directly to efficient Clifford gate sequences. We demonstrate the effectiveness of this method on key codes, achieving a 13% –44% reduction in encoder circuit gate count for the qutrit (<italic>d</italic> = 3) <inline-formula><tex-math notation="LaTeX">$[[9,5,3]]_{3}$</tex-math></inline-formula>, <inline-formula><tex-math notation="LaTeX">$[[5,1,3]]_{3}$</tex-math></inline-formula>, and <inline-formula><tex-math notation="LaTeX">$[[7,1,3]]_{3}$</tex-math></inline-formula> codes, and a 9% –21% reduction for the ququint (<italic>d</italic> = 5) <inline-formula><tex-math notation="LaTeX">$[[10,6,3]]_{5}$</tex-math></inline-formula> code when compared to prior work. We also achieved circuit depth reductions up to 42%.
Atomic physics. Constitution and properties of matter, Materials of engineering and construction. Mechanics of materials
Abstract A theoretical study of single, double and triple hydrogen-terminated chains of tellurium atoms is presented. Surprisingly, H-terminated single chains with 3 Te atoms per unit cell (as in bulk trigonal Te) are found to be unstable. They relax to regular helical structures with lower energies and smaller twist angles. However, some irregular chains are found to have still lower energies, and compact disordered H-terminated Te chains of mixed chirality are found to have even lower energies. These findings are compared with results of a new systematic study of infinite periodic Te atomic chains. Pairs of H-terminated Te atomic chains are found to form DNA-like double helices with lower energies than compact disordered structures of the two chains. Triplets of H-terminated Te atomic chains are found to form triple helices. The single, double and triple Te helices reported here are beyond the scope of previously studied periodic models with small unit cells.
V. O. Zheltonozhsky, D. E. Myznikov, A. M. Savrasov
et al.
The beta- and gamma-spectra of samples of radioactive graphite were measured from the 2nd Unit of ChNPP irradiated by bremsstrahlung gamma-beam with an end-point energy of 18 MeV. Using experimental and passport data, the mass ratio of chlorine and cobalt was determined. From the obtained data and the measured activity of 60Co in the studied samples, a method for determining the 36Cl activity was developed.
Atomic physics. Constitution and properties of matter
Abstract While the early literature on black holes focused on event horizons, subsequently it was realized that their teleological nature makes them unsuitable for many physical applications both in classical and quantum gravity. Therefore, over the past two decades, event horizons have been steadily replaced by quasi-local horizons which do not suffer from teleology. In numerical simulations event horizons can be located as an ‘after thought’ only after the entire space-time has been constructed. By contrast, quasi-local horizons naturally emerge in the course of these simulations, providing powerful gauge-invariant tools to extract physics from the numerical outputs. They also lead to interesting results in mathematical GR, providing unforeseen insights. For example, for event horizons we only have a qualitative result that their area cannot decrease, while for quasi-local horizons the increase in the area during a dynamical phase is quantitatively related to local physical processes at the horizon. In binary black hole mergers, there are interesting correlations between observables associated with quasi-local horizons and those defined at future null infinity. Finally, the quantum Hawking process is naturally described as formation and evaporation of a quasi-local horizon. This article focuses on the dynamical aspects of quasi-local horizons in classical general relativity, emphasizing recent results and ongoing research.
Atomic physics. Constitution and properties of matter
Abstract Stacking and twisting van der Waals materials provides a powerful tool to engineer quantum matter. For instance, 1T-TaS2 monolayers are Mott insulators, whereas layered 1H-TaS2 is metallic and superconducting; thus, the T/H bilayer, where heavy fermions and unconventional superconducting phases are expected from localized spins (1T) coexisting with itinerant electrons (1H), has been intensively studied. However, recent studies revealed significant charge transfer that questions this scenario. Here, we propose a T/T/H trilayer heterostructure where the T/T bilayer is a flat-dispersion band insulator with localized electrons, whereas the 1H layer remains metallic with a weak spin polarization. Varying the T/T stacking configuration tunes the flat-band filling, enabling a crossover from a doped-Mott regime to a Kondo-like state. Such a trilayer heterostructure provides, therefore, a rich novel platform to study strong correlation phenomena and unconventional superconductivity.
Materials of engineering and construction. Mechanics of materials, Atomic physics. Constitution and properties of matter
Vladimir A. Baulin, Achille Giacometti, Dmitry Fedosov
et al.
Intelligent soft matter stands at the intersection of materials science, physics, and cognitive science, promising to change how we design and interact with materials. This transformative field seeks to create materials that possess life-like capabilities, such as perception, learning, memory, and adaptive behavior. Unlike traditional materials, which typically perform static or predefined functions, intelligent soft matter dynamically interacts with its environment. It integrates multiple sensory inputs, retains experiences, and makes decisions to optimize its responses. Inspired by biological systems, these materials intend to leverage the inherent properties of soft matter: flexibility, self-evolving, and responsiveness to perform functions that mimic cognitive processes. By synthesizing current research trends and projecting their evolution, we present a forward-looking perspective on how intelligent soft matter could be constructed, with the aim of inspiring innovations in fields such as biomedical devices, adaptive robotics, and beyond. We highlight new pathways for integrating design of sensing, memory and action with internal low-power operations and discuss challenges for practical implementation of materials with "intelligent behavior". These approaches outline a path towards to more robust, versatile and scalable materials that can potentially act, compute, and "think" by their inherent intrinsic material behaviour beyond traditional smart technologies relying on external control.
The Quantum Approximate Optimization Algorithm (QAOA) has emerged as a promising variational quantum algorithm for addressing NP-hard combinatorial optimization problems. However, a significant limitation lies in optimizing its classical parameters, which is in itself an NP-hard problem. To circumvent this obstacle, initialization heuristics, enhanced problem encodings and beneficial problem scalings have been proposed. While such strategies further improve QAOA’s performance, their remaining problem is the sole utilization of local optimizers. We show that local optimization methods are inherently inadequate within the complex cost landscape of QAOA. Instead, global optimization techniques greatly improve QAOA’s performance across diverse problem instances. While global optimization generally requires high numbers of function evaluations, we demonstrate how restricted global optimizers still show better performance without requiring an exceeding amount of function evaluations.
Atomic physics. Constitution and properties of matter
Josephson junctions supply the nonlinear inductance element in superconducting qubits. In the widely used transmon configuration, where the junction is shunted by a large capacitor, the low charging energy minimizes the sensitivity of the qubit to charge noise while maintaining the necessary anharmonicity to qubit states. We report here low-frequency transport measurements on small standalone junctions and identically fabricated capacitively-shunted junctions that show two distinct features normally attributed to small capacitance junctions near zero bias: reduced switching currents and prominent finite resistance associated with phase diffusion in the current–voltage characteristic. Our transport data reveals the existence of phase fluctuations in transmons arising from intrinsic junction capacitance.
Atomic physics. Constitution and properties of matter, Materials of engineering and construction. Mechanics of materials
Henrik Thoma, Rajesh Dutta, Vladimir Hutanu
et al.
Abstract Multiferroic Ba2CuGe2O7 was anticipated as a potential member of the exciting group of materials hosting a skyrmion or vortex lattice because of its profound Dzyaloshinskii–Moriya interaction (DMI) and the absence of single ion anisotropy (SIA). This phase, however, could not be evidenced and instead, it exhibits a complex incommensurate antiferromagnetic (AFM) cycloidal structure. Its sister compound Ba2MnGe2O7, in contrast, is characterized by a relatively strong in-plane exchange interaction that competes with a non-vanishing SIA and the weak DMI, resulting in a quasi-two-dimensional commensurate AFM structure. Considering this versatility in the magnetic interactions, a mixed solid solution of Cu and Mn in Ba2Cu1−x Mn x Ge2O7 can hold an interesting playground for its interactive DMI and SIA depending on the mixed spin states of the transition metal ions towards the skyrmion physics. Here, we present a detailed study of the micro- and macroscopic spin structure of the Ba2Cu1 − x Mn x Ge2O7 solid solution series using high-resolution neutron powder diffraction techniques. We have developed a remarkably rich magnetic phase diagram as a function of the applied magnetic field and x, which consists of two end-line phases separated by a potentially quantum-critical phase at x = 0.57. An AFM conical structure at zero magnetic field is demonstrated to persist up to x = 0.50. Our results provide crucial information on the spin structure and magnetic properties, which are necessary for the general understanding and theoretical developments on multiferroicity in the frame of skyrmion type or frustrated AFM lattice where DMI and SIA play an important role.
Materials of engineering and construction. Mechanics of materials, Atomic physics. Constitution and properties of matter
The advent of quantum computing can potentially revolutionize how complex problems are solved. This article proposes a two-loop quantum-classical solution algorithm for generation scheduling by infusing quantum computing, machine learning, and distributed optimization. The aim is to facilitate employing noisy near-term quantum machines with a limited number of qubits to solve practical power system optimization problems, such as generation scheduling. The outer loop is a three-block quantum alternating direction method of multipliers (QADMM) algorithm that decomposes the generation scheduling problem into three subproblems, including one quadratically unconstrained binary optimization (QUBO) and two non-QUBOs. The inner loop is a trainable quantum approximate optimization algorithm (T-QAOA) for solving QUBO on a quantum computer. The proposed T-QAOA translates interactions of quantum-classical machines as sequential information and uses a recurrent neural network to estimate variational parameters of the quantum circuit with a proper sampling technique. The T-QAOA determines the QUBO solution in a few quantum-learner iterations instead of hundreds of iterations needed for a quantum-classical solver. The outer three-block alternating direction method of multipliers coordinates QUBO and non-QUBO solutions to obtain the solution to the original problem. The conditions under which the proposed QADMM is guaranteed to converge are discussed. Two mathematical and three generation scheduling cases are studied. Analyses performed on quantum simulators and classical computers show the effectiveness of the proposed algorithm. The advantages of T-QAOA are discussed and numerically compared with QAOA, which uses a stochastic-gradient-descent-based optimizer.
Atomic physics. Constitution and properties of matter, Materials of engineering and construction. Mechanics of materials
Benjamin Sorkin, Avraham Be'er, Haim Diamant
et al.
A major challenge in the study of active matter lies in quantitative characterization of phases and transitions between them. We show how the entropy of a collection of active objects can be used to classify regimes and spatial patterns in their collective behavior. Specifically, we estimate the contributions to the total entropy from correlations between the degrees of freedom of position and orientation. This analysis pin-points the flocking transition in the Vicsek model while clarifying the physical mechanism behind the transition. When applied to experiments on swarming Bacillus subtilis with different cell aspect ratios and overall bacterial area fractions, the entropy analysis reveals a rich phase diagram with transitions between qualitatively different swarm statistics. We discuss physical and biological implications of these findings.
In interatomic Coulombic electron capture, the capture of a free electron at an atomic center is accompanied by the radiationless transfer of the excess energy to a neighboring atom of different species, leading to ionization of the latter. We show that this interatomic process can be strongly enhanced by the presence of an additional third atom, provided the energy of the free-bound capture transition in the first atom is resonant to a dipole-allowed excitation energy in this assisting atom. The relation of the resonantly enhanced three-center electron capture with other processes is discussed, and its dependencies on the incident electron energy and the spatial geometry of the triatomic system are illustrated.
We present the status of the research in the field of atomic and molecular physics in Africa as well as some challenges hindering the efforts being made by the African scientists. We further report the discussions and progress of the African Strategy for Fundamental and Applied Physics (ASFAP) working group on Atomic and Molecular physics with the view of providing the continent research direction for next decade.
In this Chapter, we give a brief review of the state of the art of theoretical and experimental studies of synthetic magnetic fields and quantum Hall effects in ultracold atomic gases. We focus on integer, spin, and fractional Hall effects, indicate connections to topological matter, and discuss prospects for the realization of full-fledged gauge field theories where the synthetic magnetic field has its own dynamics. The advantages of these systems over traditional electronic systems are highlighted. Finally, interdisciplinary comparisons with other synthetic matter platforms based on photonic and trapped-ion systems are drawn. We hope this chapter to illustrate the exciting progress that the field has experienced in recent years.
Medical physics is a dynamic and constantly growing field of applied physics mainly directed towards the applications of physics principles to health care. Among the technological novations there is the optimization of image quality for magnetic resonance imaging, ultrasound diagnostics, and computer tomography; development and use of high energy linear accelerators with sophisticated options for dose delivery; computerized treatment planning systems, record and verification systems; overall integration of computers into the routine clinical work. The key role of the medical physicist is widely recognized to ensure the safe and effective use of modern equipment for medical exposure. Medical physicists are involved in four basic activities: clinical service, research, and development, teaching, and management/administration. In addition, they should be familiar with the safety culture and promote this principle among the medical staff for the improvement of radiation safety, setting an example by their behaviour. There is no the best practice for the certification of medical physicists in international experience. The paper presents an attempt to analyse international standards and propose recommendations for the implementation of medical physicist’ certification in Ukraine. According to the authors, this will strongly influence on nation’s health.
Atomic physics. Constitution and properties of matter
Luigi Amico, Dana Anderson, Malcolm Boshier
et al.
Atomtronics is an emerging field that aims to manipulate ultracold atom moving in matter wave circuits for both fundamental studies in quantum science and technological applications. In this colloquium, we review recent progress in matter-wave circuitry and atomtronics-based quantum technology. After a short introduction to the basic physical principles and the key experimental techniques needed to realize atomtronic systems, we describe the physics of matter-waves in simple circuits such as ring traps and two-terminal systems. The main experimental observations and outstanding questions are discussed. We also present possible applications to a broad range of quantum technologies, from quantum sensing with atom interferometry to future quantum simulation and quantum computation architectures.
In the last 25 years, much progress has been made producing and controlling Bose-Einstein condensates (BECs) and degenerate Fermi gases. The advances in trapping, cooling and tuning the interparticle interactions in these cold atom systems lead to an unprecedented amount of control that one can exert over them. This work aims to show that knowledge acquired studying cold atom systems can be applied to other fields that share similarities and analogies with them, provided that the differences are also known and taken into account. We focus on two specific fields, nuclear physics and statistical optics. The nuclear physics discussion occurs with the BCS-BEC crossover in mind, in which we compare cold Fermi gases with nuclear and neutron matter and nuclei. We connect BECs and atom lasers through both systems' matter-wave character for the analogy with statistical optics. Finally, we present some challenges that, if solved, would increase our understanding of cold atom systems and, thus, the related areas.
We calculate the cross-sections of atomic ionization by absorption of scalar particles in the energy range from a few eV to 100 keV. We consider both nonrelativistic particles (dark matter candidates) and relativistic particles which may be produced inside Sun. We provide numerical results for atoms relevant for direct dark matter searches (O, Na, Ar, Ca, Ge, I, Xe, W and Tl). We identify a crucial flaw in previous calculations and show that they overestimated the ionization cross sections by several orders of magnitude due to violation of the orthogonality of the bound and continuum electron wave functions. Using our computed cross-sections, we interpret the recent data from the Xenon1T experiment, establishing the first direct bounds on coupling of scalars to electrons. We argue that the Xenon1T excess can be explained by the emission of scalars from the Sun. While our finding is in a similar tension with astrophysical bounds as the solar axion hypothesis, we establish direct limits on scalar DM for the $\sim 1-10\,\mathrm{keV}$ mass range. We also update axio-ionization cross-sections. Numerical data files are provided.
Yu. M. Kylivnik, V. V. Tryshyn, M. V. Strilchuk
et al.
The aim of the present work is titanium silicate influence on the zinc and strontium migration in the aquatic environment. The adsorption capacity of titanium silicate toward zinc and strontium ions was investigated. With the aid of a fluorescent X-ray analyzer and energy dispersive spectroscopy the composition of the sorbent formed was determined as well as zinc and strontium presence on the surface of the sorbent after the sorption process. It was shown, that adsorption of zinc and strontium by titanium silicate strongly depends on time of interaction and solution acidity and increases with increasing of both parameters. It was established, that for the initial concentration of zinc and strontium at the level of 0.005M the presence of ions that cause the natural mineralization of water does not affect their adsorption extraction.
Atomic physics. Constitution and properties of matter